Horse != Car

I had always wondered whether or not a horse was considered a vehicle. Thanks to the Supreme Court of Pennsylvania, I now know. I really enjoy moments when lawyers and the legal system push through all adversity and common sense in the quest to make the entire edifice that is the law appear foolish. Why did a case on whether or not a horse is a vehicle get this far? Did no one exercise any common sense in the whole process? Haul the drunken horsemen in for drunk in public or some other charge and let it go.